The National Safety Council estimates that 21 percent, or 1.1 million automobile crashes, in 2010 involved people who were on their cell phone — though not all who were talking on the phone were responsible for the accident. An additional 3 percent of accidents that year involved people who were texting at the time of the crash.

The National Highway Traffic Safety Administration said that 5,474 people were killed on U.S. roadways and an additional 448,000 were injured in motor vehicle accidents involving distracted drivers in 2009.

California, Connecticut, Delaware, Maryland, Hawaii, New Jersey, and New York are among the states that ban all drivers from using a cell phone, according to the Insurance Institute for Highway Safety.